At the opposite end of the street was an upscale electronics store. Ingrid went inside alone and emerged a few minutes later with a compact high-resolution webcam. They killed an hour strolling the Croisette before returning to the hotel. Ingrid placed the camera in the window of her room and attached it to her computer with a USB cable. Then she drew the blinds and switched off the lights.

Gabriel inspected the image on the screen. “Can you record the feed?”

“Yes, of course. And better yet, I can forward it to my phone.”

“Good,” said Gabriel. “Because under no circumstances are we eating in this hotel.”

“Office doctrine?”

“It is now.”

*  *  *

The building was five floors in height, with a pair of boutiques on the ground level. The residential entrance was sandwiched between the two shops. The intercom panel listed eight apartments. The accompanying nameplates suggested that only two of the dwellings were occupied by Frenchmen. Three of the names were English-language in origin, one was Spanish, and one was German. The nameplate for Apartment 3B was empty.

By half past seven that evening, lights were burning up and down the length of the rue d’Antibes. Only four of the eight apartments showed signs of life—two on the second floor and two on the fourth. At 7:42 p.m. the lights in one of the fourth-floor apartments were extinguished, and a moment later a man and woman of retirement age emerged from the street-level door. The rigidness of their bearing suggested they were the Schmidts of 4A. Their attire suggested they were heading out to dinner.

Gabriel and Ingrid waited until nearly nine o’clock before doing the same. They left the privacy signs hanging on their doors and informed the clerk that they did not require turndown service—unnecessarily, as it was not being offered. Outside, they debated where to eat.

“One of my favorite restaurants in the world is in Cannes,” said Ingrid. “It doesn’t take reservations, and the wait for a table is terrible during the summer. But it’s perfect in the off season.”

“Am I allowed to know the name of the restaurant?”

“It’s a surprise.”

The restaurant, La Pizza Cresci, was located on the western flank of the Vieux Port, on the Quai Saint-Pierre. Inside, they were shown to a window table in the main dining room. Ingrid immediately sensed Gabriel’s discomfort.

“We can go somewhere else, if you like.”

“Why?”

“Because you look as though you’ve just seen a ghost.”

He stared silently out the window.

“Is there something you’re not telling me?”

“Search the words Abdul Aziz al-Bakari and Cannes.”

Ingrid took up her phone and typed. “Shit,” she said after a moment.

“It was a night to remember, I assure you.”

“I’m sorry, Mr. Allon. I didn’t realize.”

“It was a long time ago.”

“Let’s leave.”

“Are you kidding? It’s impossible to get into this place.”

Ingrid laughed in spite of herself. “I can’t take you anywhere.”

*  *  *

It was a few minutes after eleven when they returned to the hotel. The privacy signs were still hanging from their doors, and there was nothing to suggest that the rooms had been entered during their absence. They watched the two hours of stored video at four times the normal playback speed. The occupants of 4A had returned at 10:37 p.m., but otherwise the building’s entrance had seen no activity. By midnight the lights had dimmed in three of the four apartments, but the occupant of 2B was awake until nearly four. Ingrid reckoned they had found their man. Hackers, she explained, did their best work in the dark.

“What about the nameless occupant of the apartment upstairs?”

“It doesn’t look to me as though he’s in Cannes at the moment. Therefore, I’m betting the hacker is Martineau in 2B.”

Ingrid’s theory collapsed at half past seven when the apartment’s occupant opened the shutters. Madame Martineau was a matronly woman in her late sixties. For any number of reasons, she did not fit the profile of a typical computer hacker.

“I stand corrected,” said Ingrid.

The woman left the building at nine o’clock carrying a traditional French wicker shopping basket. Herr and Frau Schmidt went out a few minutes later, and at nine thirty “Ashworth” from 2A made her first appearance. She was a slender long-limbed woman of perhaps thirty-five with short blond hair.

“What do you think?” asked Ingrid.

“She doesn’t look like a hacker to me.”

“Neither do I, Mr. Allon. Maybe I should follow her.”

“Allow me,” said Gabriel, and headed downstairs. By the time he stepped from the hotel’s doorway, the woman was a hundred meters down the rue d’Antibes. He closed the gap to about thirty meters and followed her to a café on a small side street, where she breakfasted on café crème and a brioche before making her way to the office of a major British real estate firm. Gabriel went inside and spent a few minutes scrutinizing the available properties. The woman from 2A offered him a business card. It identified her as Fiona Ashworth, manager of the real estate firm’s Cannes branch.

Gabriel slipped the card into his pocket and started back to the hotel. On the rue d’Antibes he was surprised to see Ingrid, hastily attired in jeans and a cotton pullover, walking toward him through the bright sunlight. Something in her demeanor made him seek shelter in a pharmacy. She passed it a moment later, her eyes staring straight ahead. Smooth as silk, thought Gabriel. Very impressive, indeed.

*  *  *

He purchased a few needless toiletries from the pharmacy and returned to the hotel. Upstairs, he sat down before Ingrid’s open laptop and watched the recorded video, beginning at half past nine, when the English estate agent had left the building. Twelve minutes later, while she was having breakfast under Gabriel’s watchful eye, the shutters of Apartment 3B had swung open and its nameless occupant had appeared in the window. It turned out he was in Cannes, after all. He had sandy brown hair and an unkempt beard, and looked as though he had had a long night, perhaps several. He lit a cigarette and, expelling a lungful of smoke, gazed left and right along the street. Then he closed the shutters and disappeared from view.

But only until 10:04 a.m., when he stepped from the building’s entrance and headed east on the rue d’Antibes. He was wearing a leather jacket and looking down at the phone he carried in his right hand. Gabriel realized now that he had walked past the man a few seconds before he spotted Ingrid.

He rang her mobile.

“I’d love to chat,” she said calmly. “But I’m afraid I’m rather busy at the moment.”

“Where are you?”

“Have a look out your window.”

Gabriel did as she suggested. The man from 3B was approaching from the east. He was carrying a plastic shopping bag in his left hand and the phone in his right. Forty meters behind him, Ingrid was inspecting the merchandise displayed in the window of Zara.

“Did he go anywhere interesting?”

“The Monoprix over on the rue du Maréchal Foch.”

“What did he buy?”